1. Field of the Invention
The present invention relates to an axle driving apparatus having a common housing enclosing a pair of hydrostatic transmissions (hereinafter referred to as “HSTs”) and a pair of axles individually driven by the respective HSTs.
2. Background of the Invention
Conventionally, as disclosed in Japanese Patent Laid Open Gazette Hei. 7-323739, there is a well-known integrated hydrostatic transaxle (hereinafter referred to as an “IHT”) which is applicable for a snowblower. The IHT comprises a common housing, a pair of HSTs, each of which is a combination of a hydraulic pump and a hydraulic motor, and a pair of coaxial axles individually driven by the respective HSTs, wherein the HSTs and the axles are housed within the housing.
In the conventional IHT, in order to economically make a common construction between the left and right drive trains from the respective HSTs to the respective axles, the pair of HSTs are disposed laterally symmetrically (in the axial direction of the axles) so as to equalize lateral positions of the HSTs relative to the respective axles (in the axial direction of the axles). However, the pair of HSTs are disposed laterally symmetrically with respect to a vertical line, and the hydraulic pump and hydraulic motor of each HST are juxtaposed laterally in order to vertically downsize the IHT. Consequently, two hydraulic pump and motor pairs are laterally aligned on the substantially same vertical level so that the conventional IHT including the housing is entirely elongated laterally in the axial direction of the axles.